Valve for ventilating air-locks.



No. 838,351. PATENTED DEC. 11, 1906.

E. W. MOIR. VALVE FOB. VENTILATING AIR. LOCKS.

APPLICATION FILED JUNE 28, 1906. 5

wumssses I I INVENTQR W W ATTORNEYS m: NORRIS PETERS co., WASHINGTON, Dc.

UNITED STATES PATENT OFFICE.

ERNEST WV. MOIR, OF LONDON, ENGLAND, ASSIGNOR TO S. PEARSON & SON, INO,OF LONG ISLAND OI"Y, NEW YORK, A CORPORATION OF NE W YORK.

Specification of Letters Patent.

Patented Dec. 11, 1906.

Annlicaion filed June 28,1906. Serial No. 323,954.

To all whom it may concern.-

Be it known that I, ERNEST WV. Mom, a subect of the King of GreatBritain and Ireland, residing in London, England, have lnvented certalnnew and useful Improvements 1n Valves for Ventilating Air-Locks, ofwhich the following is a specification.

I My invention relates to automatic means for ventilating air-locksduring the lookingout operation.

This invention is intended for use in airlocks between the atmosphereand the highpressure required in tunnels, caissons, and the like.

As is well known to those familiar with the art to which this inventionrelates, the locking-out operation requires from five to fifteenminutes, according to the pressure in the tunnel, and when the lock istaxed to its utmost capacity, with the men, for example, in the changingof the shifts, the air becomes very foul in that time, as well as foggy,owing to the decompression.

It is the object of my invention to provide means for automaticallysupplying fresh air to the lock during the locking-out.

In the accompanying drawings I- have shown a preferred form of valveadapted to supply air from the tunnel, which may be consideredcomparatively fresh, as is continually being supplied thereto tomaintain constant pressure.

In the drawings, Figure 1 is a diagrammatic sectional view showingtunnel and an air-lock with my device applied therein, and Fig. 2 is alongitudinal section of a preferred form of valve.

Referring to the drawings, A represents the entrance, or the part of thetunnel at atmospheric pressure. L is the lock, and T the tunnel, havingcommunicating doors D and D in the separating-partitions.

The valve shown comprises a hollow cylindrical casing 10, open at oneend with the tunnel-pressure and having a movable perforated piston-vave11. At the other end the cylinder is open to the variable pressure ofthe air-lock through a small stationary block 12. The piston-valve 11 isrigidly connected to a piston-rod 13, which passes through a centralhole in the block 12. Also Tigidly connected to this piston-rod near themiddle is a solid piston 14. Behind the piston 14 and bearing againstthe stationary block 12 is a spring .15, adapted to be compressed by theconstant pressure of the tunnel on the reduction of pressure in thelock. -BetWeen the piston 14 and the piston-valve 11. when the valve isin its normal position (shown in Fig. 2) are number of holes 16 throughthe wall of the casing. Through these openings and the holes in thevalve 11 there is a direct communication between the tunnel and thelock.

The operation of this valve is substantially as follows: After the menenter the look from the tunnel and close the doors the ex haust-valve isopened, and the pressure in the lock immediately begins to fall. The airin the tunnel being under high pressure passes through the perforationsin the pistonvalve 11 and the holes 16 of the valve-casing, but not sorapidly as the air is leaving the lock through the exhaust-valve. At thesame time the tunnel-pressure acting on one side of the piston 14 isgreater than the lockpressure on the opposite side, which will force thepiston-valve 11 in, compressing the spring, thereby gradually coveringthe holes in the casing, so that when the pressure in the lock becomesequal to that of the atmosphere the valve 11 will have covered'all ofthe holes and stopped the inflow of air from the tunnel. In other words,while there is little difference of pressure in the tunnel and airlockmany openings 16 are provided, and these are gradually closedautomatically as the pressure falls in the air-lock and are shut offentirely at atmosphere. By these means a constant supply of justsuflicient fresh air is provided for the comfort of the men and todisperse the fog.

I claim as my invention 1. In combination with an air-lock, means forautomatically supplying fresh air thereto during the locking-outoperation.

2. In combination with a tunnel and airlock, means communicating withthe tunnel for automatically supplying air from the tunnel to the lockduring the locking-out op eration.

In testimony whereof I have signed my

